mcs/class/System.Web/System.Web.UI.WebControls/CheckBox.cs

   1 /**\r
   2  * Namespace: System.Web.UI.WebControls\r
   3  * Class:     CheckBox\r
   4  *\r
   5  * Author:  Gaurav Vaish\r
   6  * Maintainer: gvaish@iitk.ac.in\r
   7  * Contact: <my_scripts2001@yahoo.com>, <gvaish@iitk.ac.in>\r
   8  * Implementation: yes\r
   9  * Status:  100%\r
  10  *\r
  11  * (C) Gaurav Vaish (2001)\r
  12  * Thanks to Leen Toelen (toelen@hotmail.com)'s classes that helped me\r
  13  * to write the contents of the function LoadPostData(...)\r
  14  */\r
  15 \r
  16 using System;\r
  17 using System.Collections;\r
  18 using System.Collections.Specialized;\r
  19 using System.Globalization;\r
  20 using System.Web;\r
  21 using System.Web.UI;\r
  22 \r
  23 namespace System.Web.UI.WebControls\r
  24 {\r
  25         public class CheckBox : WebControl, IPostBackDataHandler\r
  26         {\r
  27                 private static readonly object CheckedChangedEvent = new object();\r
  28                 \r
  29                 public CheckBox()\r
  30                 {\r
  31                         base(HtmlTextWriterTag.Input);\r
  32                 }\r
  33                 \r
  34                 public virtual bool AutoPostBack\r
  35                 {\r
  36                         get\r
  37                         {\r
  38                                 object o = ViewState["AutoPostBack"];\r
  39                                 if(o!=null)\r
  40                                         return (bool)AutoPostBack;\r
  41                                 return false;\r
  42                         }\r
  43                         set\r
  44                         {\r
  45                                 ViewState["AutoPostBack"] = value;\r
  46                         }\r
  47                 }\r
  48                 \r
  49                 public virtual bool Checked\r
  50                 {\r
  51                         get\r
  52                         {\r
  53                                 object o = ViewState["Checked"];\r
  54                                 if(o!=null)\r
  55                                         return (bool)o;\r
  56                                 return false;\r
  57                         }\r
  58                         set\r
  59                         {\r
  60                                 ViewState["Checked"] = value;\r
  61                         }\r
  62                 }\r
  63                 \r
  64                 public virtual string Text\r
  65                 {\r
  66                         get\r
  67                         {\r
  68                                 object o = ViewState["Text"];\r
  69                                 if(o!=null)\r
  70                                         return (string)o;\r
  71                                 return String.Empty;\r
  72                         }\r
  73                         set\r
  74                         {\r
  75                                 ViewState["Text"] = value;\r
  76                         }\r
  77                 }\r
  78                 \r
  79                 private bool SaveCheckedViewState\r
  80                 {\r
  81                         get\r
  82                         {\r
  83                                 if(Events[CheckedChangedEvent] != null)\r
  84                                 {\r
  85                                         if(!Enabled)\r
  86                                                 return true;\r
  87                                         if(GetType() == typeof(CheckBox))\r
  88                                         {\r
  89                                                 return false;\r
  90                                         }\r
  91                                         if(GetType() == typeof(RadioButton))\r
  92                                         {\r
  93                                                 return false;\r
  94                                         }\r
  95                                 }\r
  96                                 return true;\r
  97                                 \r
  98                         }\r
  99                 }\r
 100                 \r
 101                 public virtual TextAlign TextAlign\r
 102                 {\r
 103                         get\r
 104                         {\r
 105                                 object o = ViewState["TextAlign"];\r
 106                                 if(o!=null)\r
 107                                         return (TextAlign)o;\r
 108                                 return TextAlign.Right;\r
 109                         }\r
 110                         set\r
 111                         {\r
 112                                 if(!System.Enum.IsDefined(typeof(TextAlign), value))\r
 113                                         throw new ArgumentException();\r
 114                                 ViewState["TextAlign"] = value;\r
 115                         }\r
 116                 }\r
 117                 \r
 118                 public event EventHandler CheckedChanged\r
 119                 {\r
 120                         add\r
 121                         {\r
 122                                 Events.AddHandler(CheckedChangedEvent, value);\r
 123                         }\r
 124                         remove\r
 125                         {\r
 126                                 Events.RemoveHandler(CheckedChangedEvent, value);\r
 127                         }\r
 128                 }\r
 129                 \r
 130                 protected virtual void OnCheckedChanged(EventArgs e)\r
 131                 {\r
 132                         if(Events!=null)\r
 133                                 {\r
 134                                         EventHandler eh = (EventHandler)(Events[CheckedChangedEvent]);\r
 135                                         if(eh!=null)\r
 136                                                 eh(this, e);\r
 137                                 }\r
 138                 }\r
 139                 \r
 140                 protected override void OnPreRender(EventArgs e)\r
 141                 {\r
 142                         if(Page!=null)\r
 143                                 {\r
 144                                         if(Enabled)\r
 145                                                 {\r
 146                                                         Page.RegisterRequiresPostBack(this);\r
 147                                                 }\r
 148                                 }\r
 149                                 if(SaveCheckedViewState)\r
 150                                         {\r
 151                                                 ViewState.SetItemDirty("checked", false);\r
 152                                         }\r
 153                 }\r
 154                 \r
 155                 protected override void Render(HtmlTextWriter writer)\r
 156                 {\r
 157                         bool hasBeginRendering = false;\r
 158                         if(ControlStyleCreated)\r
 159                                 {\r
 160                                         //TODO: Uncomment this in final version\r
 161                                         /*\r
 162                                         if(!ControlStyle.IsEmpty)\r
 163                                                 {\r
 164                                                         hasBeginRendering = true;\r
 165                                                         ControlStyle.AddAttributesToRender(writer, this);\r
 166                                                 }\r
 167                                                 */\r
 168                                 }\r
 169                                 if(!Enabled)\r
 170                                         {\r
 171                                                 hasBeginRendering = true;\r
 172                                                 writer.AddAttribute(HtmlTextWriterAttribute.Disabled, "disabled");\r
 173                                         }\r
 174                                         if(ToolTip.Length > 0)\r
 175                                                 {\r
 176                                                         hasBeginRendering = true;\r
 177                                                         writer.AddAttribute(HtmlTextWriterAttribute.Title, ToolTip);\r
 178                                                 }\r
 179                                                 if(Attributes.Count > 0)\r
 180                                                         {\r
 181                                                                 hasBeginRendering = true;\r
 182                                                                 Attributes.AddAttributes(writer);\r
 183                                                         }\r
 184                                                         if(hasBeginRendering)\r
 185                                                                 writer.RenderBeginTag(HtmlTextWriterTag.Span);\r
 186                         if(Text.Length > 0)\r
 187                                 {\r
 188                                         if(TextAlign == TextAlign.Right)\r
 189                                                 {\r
 190                                                         writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 191                                                         writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 192                                                         writer.Write(Text);\r
 193                                                         writer.RenderEndTag();\r
 194                                                         RenderInputTag(writer, ClientID);\r
 195                                                 } else\r
 196                                                         {\r
 197                                                                 RenderInputTag(writer, ClientID);\r
 198                                                                 writer.AddAttribute(HtmlTextWriterAttribute.For, ClientID);\r
 199                                                                 writer.RenderBeginTag(HtmlTextWriterTag.Label);\r
 200                                                                 writer.Write(Text);\r
 201                                                         }\r
 202                                 }\r
 203                                 if(hasBeginRendering)\r
 204                                         writer.RenderEndTag();\r
 205                         throw new NotImplementedException("Calling some internal functions");\r
 206                 }\r
 207                 \r
 208                 internal virtual void RenderInputTag(HtmlTextWriter writer, string clientId)\r
 209                 {\r
 210                         writer.AddAttribute(HtmlTextWriterAttribute.Id, clientId);\r
 211                         writer.AddAttribute(HtmlTextWriterAttribute.Type, "checkbox");\r
 212                         writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID);\r
 213                         if(Checked)\r
 214                                 {\r
 215                                         writer.AddAttribute(HtmlTextWriterAttribute.Checked, "checked");\r
 216                                 }\r
 217                                 if(AutoPostBack)\r
 218                                         {\r
 219                                                 writer.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.GetPostBackClientEvent(this, String.Empty));\r
 220                                                 writer.AddAttribute("language", "javascript");\r
 221                                         }\r
 222                                         if(AccessKey.Length > 0)\r
 223                                                 {\r
 224                                                         writer.AddAttribute(HtmlTextWriterAttribute.Accesskey, AccessKey);\r
 225                                                 }\r
 226                                                 if(TabIndex != 0)\r
 227                                                         {\r
 228                                                                 writer.AddAttribute(HtmlTextWriterAttribute.Tabindex, TabIndex.ToString(NumberFormatInfo.InvariantInfo));\r
 229                                                         }\r
 230                                                         writer.RenderBeginTag(HtmlTextWriterTag.Input);\r
 231                         writer.RenderEndTag();\r
 232                 }\r
 233                 \r
 234                 bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)\r
 235                 {\r
 236                         string postedVal = postCollection[postDataKey];\r
 237                         bool   postChecked = false;\r
 238                         if(postedVal != null)\r
 239                                 {\r
 240                                         postChecked = postedVal.Length > 0;\r
 241                                 }\r
 242                                 Checked = postChecked;\r
 243                         return (postChecked == Checked == false);\r
 244                 }\r
 245                 \r
 246                 void IPostBackDataHandler.RaisePostDataChangedEvent()\r
 247                 {\r
 248                         OnCheckedChanged(EventArgs.Empty);\r
 249                 }\r
 250         }\r
 251 }\r